Natural tapered house log milling process

ABSTRACT

A process to enable the manufacture of tapered house building logs of various diameters, which would be used in hand-crafted round log construction, in both residential and commercial applications. A milling process would remove wood to create the lateral notches, also known as grooves or copes, on the underside of each wall log, while maintaining the natural taper of each whole log used. The convex curvature of the top of each log is milled to match the concave curvature on the bottom of the log sitting directly above it, using a common curvature for specified diameters; in the process of planing the top and the underside of each log, the same degree of taper is achieved. Whole, round trees are utilized and the natural taper of each log is always maintained.

FIELD OF THE INVENTION

[0001] This invention pertains to the construction of log walls and utilizes natural tapered whole logs which are fit together and laid horizontally on top of each other. Traditionally, this type of wall construction has always been done by hand, using a chainsaw. A lateral notch, also known as a groove or cope, is cut with a chainsaw from the underside or belly of each log, and runs the fill length of each wall log. This is an extremely heavy, labour intensive and repetitive task. This invention will eliminate the time-consuming hard labour involved, but will still result in the hand-crafted look of tapered log walls. The art and craft of building with natural logs continues to gain appeal, and removing this labour intensive aspect of the construction will allow time for log builders to focus more on innovative and creative hand-crafted corner notches and other details unique to their own style of building.

DESCRIPTION OF THE PRIOR ART

[0002] There are various means by which horizontally stacked logs or milled timbers are notched or joined together. With conventional “milled” or “machine-cut” house logs, there is a huge amount of waste wood created. D-shaped logs and double tongue and groove style logs are machined out of dimensional timbers and then profiled to resemble “real logs”. Lathed (round) logs are all milled to exactly the same diameter; the tip size of the tree determines the final size of the log. An enormous amount of waste wood is generated as the log is lathed down to it's smallest dimension, often being as little as 6 inches in diameter. Up to 40% of the wood becomes waste.

[0003] Conventional milling systems are also limited in the length of logs that can be used. An unfortunate consequence is the practice of “end-butting” timbers within a wall; ie: 2-20 ft. pieces of log are butted end to end to create 1-40 ft. length. This negatively affects the building both esthetically and structurally and can cause air leak problems.

[0004] U.S. Pat. No. 4,312,161 to Goldade teaches the shaping of elongate cylindrical structural members for their interfitting in the construction of walls or similar structures. This provides an example of machine profiled timbers that have been cut from whole logs.

[0005] U.S. Pat. No. 4,903,447 to McDade teaches a variation on machine profiled logs which utilizes a double tongue and groove type of joinery and creates an exterior wall profile that resembles shiplap siding.

[0006] U.S. Pat. No. 4,510,724 to Magnuson teaches timber construction which incorporates the natural taper of the timbers and uses a uniform notching system for corner joinery. However, this system again relies on each timber being profiled to exact matching dimensions, again generating substantial amounts of wood waste and increased costs. There are machines currently utilizing curved planer heads to peel logs. As well, hydraulic equipment is being widely used in the wood manufacturing sector to position logs, align them on a determined plane, rotate them and mill them as required. Laser levellers are used in conjunction to ensure accuracy.

SUMMARY OF THE INVENTION

[0007] There is a growing world-wide shortage of timber, thus, the reduced amount of wood that is being harvested must be used to maximum advantage, achieving the highest value-added possible. This invention allows for the full utilization of each naturally tapered log used in wall construction. Essentially, only the bark and a very small portion of log are unused, and the bark can be sold as landscape mulch.

Comparative Table Showing Wood Consumption Based on Type and Size of Logs Used

[0008] Number of logs required to gain 120 inches (or 10 ft) in wall height: COMPARATIVE TABLE SHOWING WOOD CONSUMPTION BASED ON TYPE AND SIZE OF LOGS USED Number of logs required to gain 120 inches (or 10 ft) in wall height: 6″ double tongue and  20 logs high maximum obtainable length is groove 24 feet 8″ double tongue and  15 logs high maximum obtainable length is groove 24 feet 10″ round lathed logs  12 logs high 13″ average diameter logs must be used and 30-40% of the wood becomes waste; maximum obtainable length is 28 ft. 10″ tip, 16″ butt trees 9.2 logs high full length trees can be used (natural tapered logs) - 13″ (up to 55 ft.long) resulting in avenge maximum height gain per diameter round

[0009] There are also substantial savings in the cost of labour due to increased productivity when using a tapered log milling machine to create lateral grooves. It is estimated that this process will produce 6-8 times more lineal footage of lateral grooves per man day than a log builder using a chainsaw. This would allow increased time for the more individualized and creative aspects of craftsmanship involved in the log construction industry. As well, it is anticipated that the widespread use of this process would result in reduced incidence of back-related injuries now common in this industry, since the repetitive and prolonged use of the chainsaw to create lateral grooves would be eliminated.

[0010] Increased thermal mass of log buildings and higher R-values of log walls are achieved, due to the larger diameter of logs using the natural tapered milling method. Greater flexibility in design is also possible due to the long lengths of logs that can be used; no end-butting is necessary. Milled natural tapered logs would have the appearance and appeal of hand-crafted or hand-scribed joinery.

DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a section of log wall illustrating the natural taper of the logs as they lay, alternating a butt 11 (largest diameter of a log) with a tip 12 (smallest diameter of a log) and achieving level every 2 rounds (a “round” is a single layer of logs around the complete perimeter of a building).

[0012]FIG. 2 is an end view of a log wall illustrating the alternating butts 11 and tips 12 of logs and indicating common curvature 13, matching the milled convex surface of the top of each log to the milled concave surface on the underside of the log above it.

[0013]FIG. 3 is an enlarged end view of a log wall illustrating the use of a common curvature 13 on various diameters of logs resulting in the exact matching of convex to concave surfaces, joining log to log and illustrating the amount of wood removal in the process: from the underside of a log 14 and from the top side of a log 15.

DETAILED DESCRIPTION OF THE INVENTION

[0014] This process utilizes a machine to create the lateral notch, also known as a groove or cope, on the underside of a house building log and to mill a matching convex surface on the top of each log, creating walls that maintain the natural taper of each whole log used (refer to FIG. 1). Referring now to FIG. 2, 13 the convex curvature of the top of each log will be milled to match the concave curvature on the bottom of the log sitting directly above it, using a common curvature 13 for specified diameters. A 16 inch diameter curvature is defined as being equal to any portion of the perimeter of a 16 inch circle. Similarly, a 10 inch diameter curvature equals any portion of the perimeter of a 10 inch circle; refer to FIG. 3 13. The key factor in this process is to use logs of similar taper and mill them to exactly the same degree of taper. This is accomplished by positioning the log that is to be milled so that the top surface is on a horizontal plane. The concave groove is then cut into that surface. The log is then mechanically rotated 180 degrees so the opposite surface of the log is on top. Once again, hydraulic lifters and laser levellers position the log so that the top surface is essentially on a horizontal plane, with the log held in position so that the planing process results in creating the identical degree of taper in every log. A matching convex curvature is then milled on this surface. By using the same curvature throughout, no matter what diameter of log is used, level wall height is achieved every 2 rounds* (refer to FIG. 1); this is contingent upon logs being stacked so that, at each end of the wall being built, a butt 11 (or largest diameter of a log) alternates with a tip 12 (or smallest diameter of a log); refer to FIG. 1.

[0015] *A “round” is a single layer of logs around the complete perimeter of a building

[0016] In the process of milling and matching concave to convex surfaces, an extremely small amount of waste wood 14 and 15, is generated.

[0017] Trees grown in the same area have similar taper. Ideal house logs have 1 inch of taper in every 10 feet of length. If the taper is greater than that, the machine can still be used with the same results.

[0018] Cutting blades with different curvatures would be used for different diameters of logs, however, with this concept, the same curvature blade and the same degree of taper in the logs used must be maintained for any one complete building. Logs ranging from to 5 to 10 inches in diameter would use a 10″ curvature blade. Logs ranging from 10 to 16 inches in diameter would use a 16 inch curvature blade. Logs ranging form 16 to 24 inches would use a 24 inch curvature blade.

[0019] A natural tapered house log milling machine would be designed so that the machine head would move down the length of the log, as opposed to the equipment being stationary and the log being turned and moved. This would enable logs of up to 55 feet in length to be milled. 

What is claimed is:
 1. A process to construct log walls in which whole natural logs with similar taper and a maximum butt size and a minimum tip size are planed in such a way so that the same degree of taper is achieved and matching concave surfaces on the underside of every log and convex surfaces on the top of every log are created, and any given log can be stacked upon another (with gasket material in between) with the logs being reversed to one another as they are placed on the wall, so that a butt end (or largest diameter of a log) always alternates with a tip end (or smallest diameter of a log) and when the logs are stacked in a wall assembly, level wall height will always be achieved every 2 rounds, and comprising: a) whole natural logs being of similar taper; b) said logs being positioned for the first phase of milling, the cutting of the concave groove, so that the top surface of each log is on a horizontal plane; c) a concave groove of specified curvature, based on the diameter of the log, is cut into this surface, which will become the bottom of the log, once it is placed in a wall on a building; d) said logs are then rotated 180 degrees so that the opposite surface of the log is on top, and positioned so that the planing process results in an identical degree of taper being achieved; e) a matching convex curve is cut into that surface, which will become the top of the log once it is placed in a wall on a building; f) a minimal amount of waste wood being generated.
 2. This process, as claimed in claim 1, relies upon planing logs of similar taper to create logs of exactly the same degree of taper.
 3. This process, as claimed in claim 1, wherein the convex curvature of the top of each log is milled to match the concave curvature on the bottom of the log sitting directly above it, using a common curvature for specified diameters; once a common curvature has been established, that curvature must be maintained for the milling of every wall log for each particular building.
 4. This process, as claimed in claim 1, wherein a 16 inch diameter curvature is defined as being equal to any portion of the perimeter of a 16 inch circle; similarly, a 10 inch curvature equals any portion of the perimeter of a 10 inch circle; logs ranging from 5 to 10 inches in diameter would use a 10″ curvature blade, logs ranging from 10 to 16 inches in diameter would use a 16″ curvature blade and logs ranging from 16 to 24 inches in diameter would use a 24 inch curvature blade.
 5. This process, as claimed in claim 1, wherein by using the largest butt diameter of a given set of logs for a particular building, with a range in diameter of approximately 6 inches (from butt size to tip size), the curvature would be equal to, or slightly larger than, the diameter of the largest butt.
 6. This process, wherein the log wall construction as claimed in claim 1 is contingent upon on planing each log to the identical degree of taper and using a common curvature of blade throughout a particular building, and placing the logs onto the wall so that a butt alternates with a tip so that no matter what diameter of log is used, based on the established ranges, level wall height is achieved every 2 rounds. 